In today's perpendicular magnetic recording (PMR) technology, an all wrapped around (AWA) shield writer is widely used by the major hard disk drive (HDD) manufacturers. The function of a trailing shield in an AWA structure is to improve the magnetic field gradient along a down track direction which is a key requirement for high bits per inch (BPI). Meanwhile, side shields and a leading shield serve to define a narrower writer bubble which is important for realizing higher tracks per inch (TPI). In order to achieve higher area density (i.e. higher BPI and TPI) in advanced writer designs, the gap between the main pole and all shields, including the write gap adjoining the trailing shield, side gaps to the side shields, and lead gap next to the leading shield must be as narrow as possible. The material used for conventional AWA shields is a soft magnetic material without preferred anisotropy. As a result, narrowing the gap between a shield and main pole will only lead to an unwanted flux path from the main pole to the shield which in turn reduces the writability (magnetic field) of the writer on magnetic recording media. This dilemma is considered a significant challenge to improving current writer designs and performance. Furthermore, ATE and WATE are known to be largely induced with increasing write current frequency. It is expected that the aforementioned types of erasures will be a major problem for future ultra-high data rate products.
Conventional write heads have a shield structure that does not adequately address the issues of controlling the magnetic flux path for better writability and minimizing ATE and WATE to enable improved performance in advanced writer designs. Therefore, an improved magnetic shield structure is required that minimizes flux loss from the main pole to surrounding shields, and reduces ATE and WATE in ultra-high density writer designs.